DEDROBATID ALKALOIDS: Six alkaloids of the Pumpiliotoxin A series have been assigned strutures based on nmr and mass spectral comparisons With the alkaloid 251D. STEROIDS: The presence of an unusual intramolecular hydrogen bond has been demonstrated in seco-androstryn-3-01-17-one. The structure of the microsomal metabolite of spironolactone has been confirmed by C-13 nmr. PEPTIDES: cyclo (Thr-D-Val-Pro-Sar-MeAla) has been examined by C-13 nmr to allow comparison of its solution confirmation with that in the crystal.